HBV has 3 types of antigens: HBsAg, HBeAg and HBcAg, corresponding to the 3 types of antigens above are 3 types of antibodies: anti-HBs, anti-HBc and anti-HBe. The presence of these antigens and antibodies is important in determining the disease, the type of disease as well as the progression of the disease. Currently, there is a preventive vaccine, which has significantly reduced the number of people newly infected with HBV.